Guide
Planning permission for garden rooms and outbuildings
Many garden rooms, home offices, gyms and outbuildings can be built under Permitted Development — but only if they meet strict height, footprint and use rules.
Key tests
- Use must be incidental to the enjoyment of the house (not living accommodation)
- Not in front of the principal elevation
- Limited overall height; lower if within 2m of a boundary
- Combined buildings must not cover more than 50% of the garden
When it becomes a planning application
- Sleeping accommodation or self-contained living use
- Designated land or listed buildings
- Eaves or ridge heights above the Permitted Development limits
Check your project
Run the free planning check to see the likely route for your garden room.